The present invention relates to electronic data authenticity guarantee technologies.
Conventionally, the authenticity of electronic data such as electronic documents is guaranteed using an digital signature (also called “electronic signature”) technology (see, for example, Bruce Schneier, “Applied Cryptography: Protocols, Algorithms, and Source Code in C, Second Edition,” John Wiley & Sons, (Oct. 18, 1995), pp. 483-502 (hereinafter called “Document 1”).
There is also a technology for digitally signing each of entities in a structured electronic document to retrieve the structured document available for reference and editing (see, for example, JP-A-2001-167086 (FIG. 17) (hereinafter called “Document 2”).
Further, with another technology (see, for example, Ron Steinfeld, Laurence Bull, Yuliang Zheng, “Content Extraction Signatures,” in International Conference on Information Security and Cryptology ICISC 2001, volume 2288 of LNCS, pp. 285-304, Berlin, 2001, Springer-Verlag, (2001) (hereinafter called “Document 3”), from a document owned by a owner and previously signed by a signer different from the owner, part of the document permitted by the signer can be deleted from the document, the signed document can be validated after the deletion.